Hi Connie, I am seriously no expert being new to all of this myself but I have a few thoughts to share. I am BF and also expressing and not having any dramas at the moment, my daughter is 8 weeks old. If you do decide to go ahead with this - I have found out a few helpful things. I have a feeling it is to do with the type of bottles we are using. I did a heap of research and heard that the Tomee Tippee bottles were good for combining BF and bottle feeding because the teet is a similar shape to a breast. Now that DD is here, I realise that these type of bottles ARE heaps more similar to the breast than other bottles I have seen. Firstly, her lips still curl out in the same way as when she is BF. I also worried about her being fussy at the breast after introducing the bottle because the bottle would give her the milk easier. I haven't had any dramas but I have really fast let down so maybe she isn't noticing it as much.
One thing that is heaps better about BF, DD finds it MUCH more comforting than the bottle. I really doubt that she would settle as well at night just with the bottle. She accepts the bottle as a food source but drains it very quickly and then that's that. At the breast she takes heaps more time and at night really likes to gaze up at me while feeding and settles herself before we put her to bed.
All babies are different though - Good luck with whatever you decide. :)